From: Martin Uecker <uecker@tugraz.at>
Date: Sat, 1 Mar 2025 16:21:25 +0000 (+0100)
Subject: c: Fix ICE in error recovery when checking struct compatibility [PR118061]
X-Git-Tag: basepoints/gcc-16~1267
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9e834958e82219f836577da4ef8176aca2c7c9f;p=thirdparty%2Fgcc.git

c: Fix ICE in error recovery when checking struct compatibility [PR118061]

Return early when comparing two structures for compatibility
and the type of a member is erroneous.

	PR c/118061

gcc/c/ChangeLog:
	* c-typeck.cc (tagged_types_tu_compatible_p): Handle
	errors in types of struct members.

gcc/testsuite/ChangeLog:
	* gcc.dg/pr118061.c: New test.
---

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 11fa98d86ee..1a39cbb2009 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -1933,6 +1933,9 @@ tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 		ft2 = DECL_BIT_FIELD_TYPE (s2);
 	      }
 
+	    if (TREE_CODE (ft1) == ERROR_MARK || TREE_CODE (ft2) == ERROR_MARK)
+	      return false;
+
 	    data->anon_field = !DECL_NAME (s1);
 	    data->pointedto = false;
 
diff --git a/gcc/testsuite/gcc.dg/pr118061.c b/gcc/testsuite/gcc.dg/pr118061.c
new file mode 100644
index 00000000000..6efc94d9e3b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr118061.c
@@ -0,0 +1,8 @@
+/* { dg-do "compile" } */
+/* { dg-options "-std=gnu23" } */
+
+int main()
+{
+    struct { int x[1++]; } x;	/* { dg-error "lvalue required as increment operand" } */
+    struct { int x[1++]; } y;	/* { dg-error "lvalue required as increment operand" } */
+}